According to the Long Term Evolution (LTE) standard, a cell search process is carried out whereby a receiver synchronizes with a cell. The cell broadcasts a primary synchronization signal (PSS) used for timing and frequency acquisition and a secondary synchronization signal (SSS) used to acquire information related to the cell. Each of the PSS and SSS constitutes a period timing reference which is repeated every 5 ms.
FIG. 1 shows the structure of an LTE downlink radio frame 10. The 10 ms radio frame 10 is divided into ten 1 ms sub-frames 12, with each sub-frame 12 being split into 0.5 ms slots, each slot containing seven symbols. In an FDD cell, as shown in FIG. 1, the PSS 14 is transmitted as the last symbol of the first and eleventh slots of the frame 10, and the SSS is transmitted as the preceding symbol. In a TDD cell (not shown), the PSS is transmitted as the third symbol of the third and thirteenth slots, with the SSS being transmitted three symbols earlier. Thus, whether the cell uses FDD or TDD, the PSS and SSS each appear in the same position during each half radio frame, thereby being transmitted every 5 ms.